Our current type definitions of the @sentry/cli JS interface are not 100% correct/adhered to and allowed for some nasty bugs to sneak in (e.g. #2062). We should enable TypeScript type checking.

I think this would be an ideal case for JS-based TypeScript type checking where we don't transpile anything or write actual TS but type check via JSDoc. Given we already use type information in JSDoc this should be a seamless transition and we get type safety for cheap.